/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    AllFilter.java
 *    Copyright (C) 1999-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters;

import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;

/**
 * A simple instance filter that passes all instances directly through.
 * Basically just for testing purposes.
 *
 * @author Len Trigg (trigg@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class AllFilter extends Filter implements Sourcable, WeightedAttributesHandler, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = 5022109283147503266L;

    /**
     * Returns a string describing this filter
     *
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {
        return "An instance filter that passes all instances through unmodified." + " Primarily for testing purposes.";
    }

    /**
     * Returns the Capabilities of this filter.
     *
     * @return the capabilities of this object
     * @see Capabilities
     */
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     *
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws Exception if something goes wrong
     */
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);
        setOutputFormat(instanceInfo);
        return true;
    }

    /**
     * Input an instance for filtering. Ordinarily the instance is processed and
     * made available for output immediately. Some filters require all instances be
     * read before producing output.
     *
     * @param instance the input instance
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input format has been defined.
     */
    public boolean input(Instance instance) {

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }
        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }
        if (instance.dataset() == null) {
            push((Instance) instance.copy());
        } else {
            push(instance); // push() will make a copy anyway.
        }
        return true;
    }

    /**
     * Returns a string that describes the filter as source. The filter will be
     * contained in a class with the given name (there may be auxiliary classes),
     * and will contain two methods with these signatures:
     * 
     * <pre>
     * <code>
     * // converts one row
     * public static Object[] filter(Object[] i);
     * // converts a full dataset (first dimension is row index)
     * public static Object[][] filter(Object[][] i);
     * </code>
     * </pre>
     * 
     * where the array <code>i</code> contains elements that are either Double,
     * String, with missing values represented as null. The generated code is public
     * domain and comes with no warranty.
     *
     * @param className the name that should be given to the source class.
     * @param data      the dataset used for initializing the filter
     * @return the object source described by a string
     * @throws Exception if the source can't be computed
     */
    public String toSource(String className, Instances data) throws Exception {
        StringBuffer result;

        result = new StringBuffer();

        result.append("class " + className + " {\n");
        result.append("\n");
        result.append("  /**\n");
        result.append("   * filters a single row\n");
        result.append("   * \n");
        result.append("   * @param i the row to process\n");
        result.append("   * @return the processed row\n");
        result.append("   */\n");
        result.append("  public static Object[] filter(Object[] i) {\n");
        result.append("    return i;\n");
        result.append("  }\n");
        result.append("\n");
        result.append("  /**\n");
        result.append("   * filters multiple rows\n");
        result.append("   * \n");
        result.append("   * @param i the rows to process\n");
        result.append("   * @return the processed rows\n");
        result.append("   */\n");
        result.append("  public static Object[][] filter(Object[][] i) {\n");
        result.append("    return i;\n");
        result.append("  }\n");
        result.append("}\n");

        return result.toString();
    }

    /**
     * Main method for testing this class.
     *
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new AllFilter(), argv);
    }
}
